Effect of Atomic Ordering on the Magnetic Structure of the MnPd3 Phase

Neutron diffraction and magnetic susceptibility measurements were performed on the MnPd3 phase in both completely ordered and partially disordered states. The antiferromagnetic configuration of MnPd3 was confirmed in the range of 23–30 at.% Mn. The angle φc of the magnetic moments to the tetragonal axis, which is 0° below 25% and 90° at higher Mn concentrations, was observed to become atomic order‐dependent at 25%, increasing from 0° towards 90° with decreasing order. A decrease in the Neel temperature with decreasing order was also observed. The 90° turn in the direction of the magnetic moments is thought to be due to the effect of the nearest‐neighbor Mn pairs which are formed either because of the partial disorder of the stoichiometric alloy or owing to the excess Mn atoms in the ordered nonstoichiometric alloys.